| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 1 |
0.3%
|
|
| 2007 | 5 |
1.3%
|
|
| 2008 | 17 |
4.4%
|
|
| 2009 | 37 |
9.5%
|
|
| 2010 | 136 |
35%
|
|
| 2011 | 180 |
46.3%
|
|
| 9997 | Inconsistent (Secondary Editing) | 4 |
1%
|
| 9999 | Missing | 9 |
2.3%
|
| Sysmiss | 4383 |